Process of manufacturing parts of brush-holders and similar devices.



J. M. BARR. PROGESS OP MANUFAGTUBING PAETS OF BBUSE EOLDERS AND SIMILAR DBVICES. APPLIUATOH PILED JAN. 11, 1909.

969,5 1 1 Patented Sept. 6, 1910.

I z x/ INVENTOR fl, 7%.

BY E 7 A'TTORNEY UNITED s'ma* PATENT GREECE.

JOHN M. BARR, OF PITTSBURG. PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEG- TRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

PROCESS OF MANUFACTURING PARTS BRUSH-HOLDERS AND SIMILR DEVICES.

To aZZ whom it may concern:

Be it known that l, JOHN M. BARR, a citizen ot' the United States, and a resident of Pittsburg, in the eounty of Allegheny and State of Penusylvania, have invented a new and useful Improvement in Processes of Manufaeturing Parts of Brush-Holders and Similar Devices, of which the following is a. specification.

My invention relates to the mantaeture ot' brusl holders and similar electrical appliances, and it has tor its object to provide a-novcl process ot' construeting the aforosaid parts that shall be inexpensivc in pei formanee and produetive of speeialh' accurate results.

In order to avoid the expense ot machiniug east metal parts. a die casting process ot' forcing nolten metal into steel dies or nolds, under heavy prcssure, has herctofore been cnployed. While very satisfactory results may be seeured in this way, the composition of the metal ot' which the eastings are made is obvionsly restricted, in a general way, to such alloys as are free froni porosty, have only a shght shrnkage :uu` produee a body having a close, fine gram. The

alloys usually employed contain zine, among other well known metallic ingredients. For eneral purposes, the metal castings so prouced are not rendered less serviceable by reason of the zine, but, if these alloys are used in the nanufactu'e ot the parts ot' brush holders and other elcctrie devices which conduct eleetrie current, the zine is volatilized and the surtaces become pittcd.

According to ny novel process ot' manufaeture, I provide a liniug ot eopper, brass or other suitable material tor the surtaees ot' the deviee which are engaged by currentcarrying parts such as a carbon contact brush, and secure the linug in position by molding it in place by the die casting process above efcrrcd to. By this means, the lining material is snoothcd out' and accurately and tirmly located En the desired position by contact. with the :au-faces ot' the die against which it is forced by the nolten alloy that constitutes the body of the casting and which is forced into the mold by means of a plunget. or force punip, in accordanee with the methods used n die casting.

My invention is ilhstrated in the aceom- .panying drawings, in which Fignres l and 2 are, respeetively', a plan Specification of Letters Patent.

Application filed January 11, 1909.

ducing such holes :s are found in the brush Patented Sept, 6, 1910. Serial No. &71,645.

and an eleva'tion of `a brush holder part showing the location 'of the lining which l utdize in ny process of manutaetnre. Fig. 3 s a seetional elevation of a well known type ot' die casting machine.

Reterring til-st to Fig. 3 of the drawings the deriee illustrated coniprises a mold 1 which is placed over the melting pot 2 in a horizontal position, a gas burner or heat produce; 3, a charging ehute 4, a cylinder 5 communicating with the melting pot, and a piston (3 operating in the cylinder. A conuuuication is established from the melting' pot to the nold through a nozzle T, and, when the metal in the pot is heated to the proper temperature, the piston is forced into the cylinder by means of a lover 8, and the moltcn metal is thereby forced rapidly through the nozzle 7 into the mol'd which is completely filled before the metal begins to eool. The shape of the nold will, ot' course, depend upon the desired form of the castingto be produced. Instead of the usnal cores, steel rods or bloeks are enployed for proholder hereinat'ter described for the reception of the carbon brnsh and for the nsual supporting rod or bar. The mold is then removed and opened and the process repeated.

ltet'ering now to Figs. l and 2, the brnsh holder part illustrated eonpriscs a box 9 in which a carhon brush or current eollector may be adjustably supported, a clamping nenber 10 which is adaptcd to fit over a stationary rod or bar and side members 11 which join the box t) to the clamping member 10. The surface of the clamping niembcr which is adjacent to the supporting rod or bar and the inner surface ot' the box lt) are lined with eoatings or sur-tacos 12 of sheet coppcr or brass which arc so wrapped around the core rods or blocks in the nold during thc casting process as to become integral with the casting. It' thin linings were inserted iu ordinary nolds they would beeouc part ot' the casting` but they would not keep their shape sutliciently to bo ot' service without machinng. Ilowever, when 'thin sheet. metal linings are used in my process, prcssurc in'oduced in the molten metal is sutlicient to smooth out. and to shape the liuings accuratcly to the core members` I desire 'that variations from the process described which do 'not depart from* the 119 pr m'e to form the lnngs.

2. Tha process of nmmctnrng pa'ts et the Walls of u die o' nold to consttu'te linings for the electrc contact surfaces, and then frcing molten metal suitable for die casting into the die 01' mold under pressure,

thereby forcing 'the linng parts against the w lls of the die 01' mold to accurately form the stu-faces of the lining and to make the same integral With the casting.

In testmony whereof, I have hereunto subsc'bed my name this 31s'b day of Decemher, 1908.

. J OHN M. BARR.

Vitnesses:

CHAS. W. J OHN/SON, BIRNEY HINES. 

